Improvement in molds for forming artificial teeth



NlTE STATES PATENT ries.

J. TERRELL, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN MOLDS FOR FORMING ARTIFICIAL TEETH.

Specification forming part of Letters Patent No. 40,58 I dated November10, 1863.

To all whom it may concern Be it known that I, JOHN TERRELL, ofPhiladelphia, Pennsylvania, have invented certain Improvements in Moldsfor Artificial Teeth; and I do hereby declare the following to be afull, clear, and exact description of the same, reference being bad tothe accompanying drawings, and to the letters of reference markedthereon.

My invention consists of certain improvements, described hereinafter, inmolds for forming artificial teeth, my said improvements having beendesigned with the view of makin g depressions in the bases of the teeth,and of removing the teeth from the molds after the depressions have beenmade; also of making in the teeth longitudinal openings c'oinmunicatingwith the said depressions, the teeth thus formed being particularly welladapted for being fastened to vnlcanizablegum plates and to each other.

In order to enable others skilled in the art to make and use myinvention, I will now proceed to describe its construction andoperation.

On reference to the accompanying drawings, which form a part of thisspecification, Figure 1 is a plan view, with the topremoved, of myimproved mold. for forming artificial teeth; Fig. 2, a transversesection on theline 1 2, Fig. 1; Fig. 3, a longitudinal section on theline 3 4, Fig. l 5 and Figs. 4, 5, sectional views, drawn to an enlargedscale, of the teeth made by the mold.

A is the bottom plate of the mold, the center of which, throughout itslength between the points 00 0c, Fig.1, is a plain surface. That portionof the mold between the points 00 and the sides of the same is raisedabove the level of the central part in the form of a succession ofarched projections, B BB, Fig. 3, the central portion of each projectionbeing cut away in order to admit a block, 0, on the inner face of whichare one or more projec-' tions, a, these blocks 0 being permanentlysecured in their places by pins 6.

D and D are strips of metal, in which are out, at points opposite theblocks 0, depressions c a, corresponding to the form which it is desiredto give to the backs and crowns of the teeth, the said strips beingseparated from each other by a Wedge-formed key, E, which serves to keepthem pressed tightly against the inner sides of the raised portion ofthe mold. The cap of the mold (shown in dotted lines, Fig. 2) resemblesthose generally used in molds for casting teeth. G and G are pins, whichcan beintrod uced into the molds through suitable openings in the endsof the same, the said pins when in the molds occupying sucha positionthat they project across the faces of the block 0 and just touch theends of the projections a, any portion of the mold which would interferewith the introduction of the pin being cut away. When teeth are to beformed in the molds, the'pins G are removed and the plastic material, ofwhich the teeth are to be made, introduced, care being taken that thematerial penetrates all the interstices below and around the projectionsa. The cap of the mold is then secured in its place, the pins Gintroduced, and, if necessary, immediately withdrawn, and the moldheated until the material therein is sufficiently baked. The cap of themold is then detached and one key, E, removed, which permits one of thestrips, D, to be moved back until it strikes the side of the other. Thebaked material (now in the form of blocks of teeth) may then be removedby sliding each block forward, so as to release the rear of the samefrom the projection a, and then lifting it from the mold. When alltheblocks on one side have been removed, the other strip, D, may be movedback, and the operation repeated on the other side. It will be foundthat the blocks of teeth cast in this manner have oblong or other shapeddepressions in their bases corresponding to the shape of the projectionsa, and that these depressions communicate with an opening (made by thepins Gr)- which passes longitudinally through the block. This will bebest understood by referring to the enlarged views of the teeth in Figs.4 and 5, Fig. 4 being a transverse section of the block of teeth, andFig. 5 a longitudinal section on the line 5 6, Fig. 4, the red linesshowing the direction taken by the pins Gr through the block of teeth,the depressions in which are made between the points on m and n a by theprojections a.

It will be apparent that the molds may be formed so as to makedepressions of any shape and size in the bases of blocks of teeth forsecuring the same to vulcanizable-gum bases and to each other,

It should be understood that when the mold is in a finished state theblocks 0 are permanently secured in their places, the only object inmaking them separate from the mold in the first instance being that theprojections a may be more readily formed.

I am aware that depressions have been made in the bases of teeth byforming projections in the mold, but these projections have been formedon blocks arranged to slide outward, so that the teeth might be removed,Whereas in my mold the projections for forming the depressions in theteeth are station ary, the removal of the teeth being effected after theWithdrawal of the key E and the moving of the strips D and D in themanner described above.

I do not desire to claim of themselves the movable strips D and D, asthey have been heretofore used in molds, butfi'or no other purpose thanthat of forming the crowns of the teeth.

I claim as my invention and desire to scour by Letters Patent- 1. Thestationary projections to, for forming recesses in the teeth, incombination with the key E and movable strips D, for permitting theteeth to be withdra wn'from the said projections in the mannerdescribed.

2. The employment of the movable pins G in the manner and for thepurpose described.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

JOHN TERRELL.

Witnesses H. HoWsoN, C. HoWsoN.

